[U-Boot] [PATCH v2 1/5] efi_loader: bootmgr: support BootNext and BootCurrent variable behavior

[AKASHI Takahiro <takahiro.akashi@linaro.org>]

On Tue, Feb 26, 2019 at 07:57:26PM +0100, Heinrich Schuchardt wrote:
> On 1/15/19 3:54 AM, AKASHI Takahiro wrote:
> > See UEFI v2.7, section 3.1.2 for details of the specification.
> > 
> > With my efitool command, you can try as the following:
> >   => efi boot add 1 SHELL ...
> >   => efi boot add 2 HELLO ...
> >   => efi boot order 1 2
> >   => efi bootmgr
> >      (starting SHELL ...)
> >   => efi boot next 2
> >   => efi bootmgr
> >      (starting HELLO ...)
> >   => efi dumpvar
> >   <snip ...>
> >   BootCurrent: {boot,run}(blob)
> >   00000000:  02 00                    ..
> >   BootOrder: {boot,run}(blob)
> >   00000000:  01 00 02 00              ....
> > 
> > Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
> > ---
> >  lib/efi_loader/efi_bootmgr.c | 34 +++++++++++++++++++++++++++++++++-
> >  1 file changed, 33 insertions(+), 1 deletion(-)
> > 
> > diff --git a/lib/efi_loader/efi_bootmgr.c b/lib/efi_loader/efi_bootmgr.c
> > index a095df3f540b..6c5303736dc6 100644
> > --- a/lib/efi_loader/efi_bootmgr.c
> > +++ b/lib/efi_loader/efi_bootmgr.c
> > @@ -145,11 +145,21 @@ static void *try_load_entry(uint16_t n, struct efi_device_path **device_path,
> >  	efi_deserialize_load_option(&lo, load_option);
> >  
> >  	if (lo.attributes & LOAD_OPTION_ACTIVE) {
> > +		u32 attributes;
> >  		efi_status_t ret;
> >  
> >  		debug("%s: trying to load \"%ls\" from %pD\n",
> >  		      __func__, lo.label, lo.file_path);
> >  
> > +		attributes = EFI_VARIABLE_BOOTSERVICE_ACCESS |
> > +			     EFI_VARIABLE_RUNTIME_ACCESS;
> > +		size = sizeof(n);
> > +		ret = rs->set_variable(L"BootCurrent",
> > +				       (efi_guid_t *)&efi_global_variable_guid,
> 
> Use EFI_CALL().

Okay
But as I said somewhere else, it's quite annoying to me that
some efi_xxx requires EFI_CALL(), and others not.
There should have been consistent naming rules.

> Instead of dereferencing you could directly call
> efi_set_variable().

Yeah, given that this code is under lib/efi_loader, it may be natural
to use efi_set_variable(). But existing get_var() uses the same style of coding.

Do you want to change all of the call sites including get_var()?

> > +				       attributes, size, &n);
> > +		if (ret != EFI_SUCCESS)
> > +			goto error;
> > +
> >  		ret = efi_load_image_from_path(lo.file_path, &image);
> >  
> >  		if (ret != EFI_SUCCESS)
> > @@ -173,16 +183,38 @@ error:
> >  void *efi_bootmgr_load(struct efi_device_path **device_path,
> >  		       struct efi_device_path **file_path)
> >  {
> > -	uint16_t *bootorder;
> > +	u16 bootnext, *bootorder;
> >  	efi_uintn_t size;
> >  	void *image = NULL;
> >  	int i, num;
> > +	efi_status_t ret;
> >  
> >  	__efi_entry_check();
> >  
> >  	bs = systab.boottime;
> >  	rs = systab.runtime;
> >  
> > +	/* get BootNext */
> > +	size = sizeof(bootnext);
> > +	ret = rs->get_variable(L"BootNext",
> > +			       (efi_guid_t *)&efi_global_variable_guid,
> > +			       NULL, &size, &bootnext);
> 
> You could call efi_get_variable() directly instead of dereferencing rs.
> But anyway you have to use EFI_CALL().

Ditto

> > +	if (!bootnext)
> > +		goto run_list;
> 
> Goto is acceptable for error handling. But otherwise I would rather
> avoid it.

Okay with another indentation.

> > +
> > +	/* delete BootNext */
> > +	ret = rs->set_variable(L"BootNext",
> > +			       (efi_guid_t *)&efi_global_variable_guid,
> > +			       0, 0, &bootnext);
> 
> EFI_CALL().

Thanks,
-Takahiro Akashi

> Best regards
> 
> Heinrich
> 
> > +	if (ret != EFI_SUCCESS)
> > +		goto error;
> > +
> > +	image = try_load_entry(bootnext, device_path, file_path);
> > +	if (image)
> > +		goto error;
> > +
> > +run_list:
> > +	/* BootOrder */
> >  	bootorder = get_var(L"BootOrder", &efi_global_variable_guid, &size);
> >  	if (!bootorder)
> >  		goto error;
> > 
>